I've been watching the crack slowly spread over the years. Little by little... It was obviously time to replace it once I started to hear a faint chirping noise, the sound of the fan blade coming in-contact with fan housing! I don't want to think what damage that would have caused.

I love the finish of the new fan, is this how them come now?
I wasn't sure if my shop sprayed it with someone or not.






Back side of fan view

 

My fan also looks like your new one which makes me think it was replaced at some point. The new fans are definitely nice and they clean up easily.

I never realized that these fans could fail like that. I had heard about stress cracks but that looks really bad! Was it just the one blade or were cracks forming on other blades also?

 

There were other cracks as well, but not as severe. I had marked the ends of the crack with a permanent marker, and watched it slowly spread over at least 5 years.

Thanks for confirming that your fan has a similar finish. It does look nice, and the gloss should help keep it looking clean for the next 20 years!

 

My new one is the same as yours

 

Did your new fans come coated? Where did you purchase?

 

These are all factory fans. Sunset has good pricing on them, like $485. 964-106-015-40 as I recall. They are painted/coated, and have a new hub bearing. The hub beariing is maybe $180 by itself.

Mine was cracking at the hub, and then I found the bearing was going out once I pulled the fan. All of these fans are getting long in the tooth, and I've seen some really bad ones...

Mine, cracking....then the new one.

 

So cool looking. Makes me want one just because... :->

 

If I remember right there are 3 or so different numbers or at least there was 5 or so years ago when mine started falling apart so be sure you order the correct one.

 

^^^^^^ Just happened to have PET open at the moment.......

 

These should not fail like that without extenuating circumstances. I was looking at a one owner 240k mile 90 a few weeks back. The owner said it was the original fan and his showed no signs of cracks. Something must have impacted the blade at one point to cause it to crack. Although he does remove it every 10 years or and repaint it after inspecting it. Something we should all do. Once they crack however it is just a matter of time. If they do crack fill the crack with paint to prevent corrosion from setting in. It is smart to mark the crack afterwards to check to see if it gets worse over time. Although once they are cracked to that degree it makes sense to replace. It is a small price to pay.

BTW what pulley is that?

 

Yup.
Or... drilling stop-cracks (at first sign) at both ends of crack's length for the short term?

...Nah.

This isn't war-time necessity, and the price for new isn't THAT hideous.

 

Maybe in aluminum but not magnesium. Corrosion is the biggest enemy. You would be surprised how strong mag can be. It is the elements getting into the crack that causes them to get worse and fail. Sometimes you want to drive them and do the work over the winter driving break. Protecting them from the elements will give you more time than you realize assuming they haven't gotten as bad as the one pictured.

 

John or me?

I think stock pulley (just changed spacers??), with Rothsport RS conversion hub.
http://www.rothsport.com/Products/En...ersion-Hub.htm

 

Thanks, Yours i think John's is still in process. Looking good to both. It is amazing how much better the engine compartment looks with a clean fan and fresh sound deadening.

 

Yes, still in progress. I hope to have my custom billet valve covers tomorrow and can get the engine ready for installation over the next week before another month of work travel.